Valve with axially spaced guides and bellows operator

ABSTRACT

A valve having a straight tubular housing is provided with a transverse valve seat and a valve disc mounted on a stem having two axially spaced portions which are guided by elements fixed on the valve housing for precisely axial movement of the valve disc toward and away from the valve seat. The valve stem is moved by pressure fluid in bellows in one direction, and by a return spring and/or pressure of the controlled fluid in the other direction.

9 l I M United States Met [15] 3,3 17 Burger 1 Ian. 1111/ M72 [54] VALVEWITH AXIIALLY SPAtCED 2,631,600 3/1953 Flanagan 1 37/269 GUIDES ANDBELLOWS OPERATUR 2,679,259 5/l954 Haeberlein. 25l/6l.4 X

3,493,008 2/1970 Slaglione ..137/219 [72] Inventor: Manfred Burger,Munich, Germany I FOREIGN PATENTS OR APPLICATIONS [73] Assignee: DanielStephen Delany, London, England part interest 1 Germany 1 1 1 .4

[22] Filed: 1969 Primary Examiner-Arnold Rosenthal 2 App] No.I 87 01Attorney-Kelman & Berman [57] ABSTRACT [30] Foreign Application PriorityData g y A valve having a straight tubular housing IS provided with a y5, 1969 Germany 19 22 886-5 transverse valve seat and a valve discmounted on a stem having two axially spaced portions which are guided byelements Cl 251/614, fixed on the valve housing for precisely axialmovement of the 251/282 valve disc toward and away from the valve seat.The valve [51] lint. C1 ..Fl61( 31/145, F16k 41/10 tem is movgd bypressure in bellows in one direction, 1 Field 11 Search and by a returnspring and/or pressure of the controlled fluid 2 1/ in the otherdirection.

I 56] References Cited 12 Claims, 6 Drawing Figures UNITED STATESPATENTS 1,294,151 2/1919 Page ..137/271 X 2h I6 Z8 51] 52 201-58 59 E i5L VALVE WliTlll AXIALLY SPACED GlUlllDBfi AND IBIELILOWS OFIERATOERThis invention relates to valves, and particularly to a straight-wayvalve whose inlet and outlet nipples are coaxially aligned with thevalve housing.

In its more specific aspects, the invention is concerned with improvedstraight-way valves equipped with bellows in the valve housing, oneaxial end of the bellows being mounted on a spider, and the other axialend being fastened to a valve body for movement with the latter towardand away from a position in which the valve member seals an aperture ina valve seat transverse to the housing axis.

An object of the invention is the provision of such a valve in whichperfect seating of the valve member on the valve seat is ensured byadequate guiding of the valve member toward and away from theaforementioned position.

The known valves of the aforedescribed type require frequent maintenancebecause the valve member is not precisely aligned with the valve seat,and stresses are asymmetrically distributed in the valve member, thevalve seat and particularly the bellows of the valve, thereby causingrelatively rapid wear.

It has now been found that the useful life of a valve of the generaltype described above can be extended significantly and its reliabilityincreased by precisely guiding the valve member toward and away from thevalve seat in an axial direction.

According to the invention, the principal elements of the valve thusinclude a housing having two axial ends open for flow of a fluid throughthe housing in the direction of its axis, a valve seat member in thehousing defining an aperture extending through the valve seat member insaid direction, and a valve member axially movable in the housing towardand away from a position of engagement with the valve seat member inwhich the valve member seals the aperture in the valve seat member. Oneaxial end ofa bellows member, which is axially expandable andcontractable in the housing is fixedly fastened to a spider arrangementwhich itself is fixedly fastened in the housing. A conduit communicateswith the otherwise sealed chamber in the bellows for flow of fluid intoand out of the chamber. A motion transmitting linkage connects the otheraxial end of the bellows to the valve member for moving the valve membertoward and away from its aforementioned position during expansion andcontraction of the bellows. A guide arrangement guides the valve memberin an axial direction.

The preferred motion transmitting linkage consists essentially of avalve stem which is fastened to the valve member and to the bellows, andwhich is engaged by the guide arrangement.

Other features, additional objects and many of the attendant advantagesof this invention will readily become apparent from the followingdetailed description of preferred embodiments when considered inconjunction with the appended drawing in which:

FIG. 1 shows a tubular shutoff valve of the invention in axial section;

FIG. 2 illustrates a valve closely similar to that of FIG. 1 in acorresponding view;

FIG. 3 shows a valve of the invention and an associated controlapparatus in section partly on the axis of the valve;

FIGS. 4 and 5 illustrate respective additional valves of the inventionin axial section; and

FIG. 6 shows the valve of FIG. 5 in radial section on the line Vl-VI.

Referring now to the drawing in detail, and initially to FIG. 1, thereis seen a cylindrical shell or valve housing 10 whose cavity is axiallybounded by a centrally apertured end wall 121 and a peripherallyapertured end wall 16. The end walls 121, 16 are flanged between annularend faces of the housing 10 and between an inlet nipple 22 and an outletnipple 24 respectively.

The nipples 22, 2 1 and the housing 10 are aluminum castings whoseinternal surfaces are protected against the corrosive effects of thefluid passing straight through the valve by tubular linings 61, 62, 03of austenitic stainless steel, and the end walls 121, 16 are made of thesame material. To provide adequate anchorage for the screws which passthrough the end walls and attach the nipples to the housing 10, a steelring Ml is coaxially cast into the wall of the housing near one axialend, and provided with threaded bores, and internally threaded sleeves65 are embedded in the other axial end of the housing 10 incircumferentially spaced relationship. a

The apertured central portion of the end wall 121 is axially offset fromthe flanged periphery of the wall, and the shoulder formed by the offsetprovides a valve seat 141 normally en gaged by a conically taperingvalve disc 321 of somewhat resilient plastic. There are enough axialpassages arranged in a circle about the housing axis in the centralportion of the end wall 121 to reduce the flow resistance of the wall toa minimum, and to leave radial spokes 53 supporting a central spider 54in which a cylindrical valve stem 301 is axially guided.

One end of the stem 301 is fixedly fastened to the valve disc 321. Ahelical compression spring 57 is coiled about the stern 301. One end ofthe spring abuts against the spider 50, and the other end abuts againstthe bottom wall] 60 of a narrow cupshaped receptacle 58 which spacedlyand coaxially envelops the spring 57. The other end of the stern 301passes through the bottom wall 60 and intoa blind bore 55 in the axiallyenlarged central portion 50 of the end wall 16 which is surrounded bya-circular row of axial passages near the periphery of the end wall 16,leaving radial spokes 10. The stem 301 is fixedly fastened and sealed tothe bottom wall 60.

A bellows 201 is coaxially fastened to the central wall portion 56 andto the rim 59 of the receptacle 50. A conduit 23 leads from a radialface of the wall portion 56 in the interior of the bellows 201 throughthe end wall 16 and radially outward of the valve for connection to asource of fluid under pressure.

The valve disc 321 is normally held against the seat 141 by the spring57, by the axially tensioned bellows 201, and by the pressure of thefluid controlled by the valve which flows in the direction of the arrowA when the valve is opened. The valve is opened for practically straightflow of fluid from the inlet nipple 22 to the outlet nipple 24 whencontrol fluid under sufficient pressure is admitted to the bellows 201through the conduit 28. The valve disc 321 is precisely guided towardand away from the valve seat 141 by the stem 301 whose two ends arecentered in the spider 54 and in the spiderlike central portion 56 ofthe end wall 16.

Because of the proximity of the spider 54 to the junction between thestern 301 and the valve disc 321, the disc is engaged with the valveseat 1411 in precise alignment without radial play or deviation. Thespring 57 which biases the valve disc 321 toward the closed positionreduces the stresses in the bellows 301 and extends the useful life spanof the bellows by preventing overextension of the bellows. The valvecloses promptly and securely even if the valve disc 321 and the valveseat 141 should be slightly worn or contaminated with solids. The axiallength of the valve is not significantly increased by the spring becauseof the provision of the receptacle 58.

The normally open valve illustrated in FIG. 2 differs from theaforedescribed valve mainly by a reversal of the end wall 121 whosevalve seat M1 faces the bellows .201, whereas the valve seat in FIG. 11faces outwardly toward the inlet nipple 22. The two ends of a stern 302closely similar to the stem 301 are respectively received in the bore ofthe spider 541 and in the blind bore 55 of the spiderlike centralportion 56 of the end wall 16. The stem passes centrally through a valvedisc 322, not otherwise different from the afore-described valve disc321, and is normally held spaced from the valve seat 1 11 toward thebellows 201 by a short helical compression spring 66 which replaces thespring 57 described above.

The valve disc 322 is moved against the valve seat 141 in precisealignment when the bellows 201 is inflated and axially expanded bypressure fluid admitted through the conduit 28.

The spring 66 which biases the valve disc 322 toward its normal positionreduces stresses in the bellows 201 and thereby improves the reliabilityof the valve. The useful life of the bellows is also extended by thefact that two axially widely spaced portions of the stem 302 are guidedin elements fixed to the valve housing so that the bellows is notsubject to stresses transverse to its axis.

The valve illustrated in FIG. 3 is similar to that shown in FIG. 1. Ithas a cylindrical valve housing 10 whose cavity is axially bounded byapertured end walls 12 and 16. An outwardly facing valve seat 14 aboutthe central aperture of the end wall 12 is normally engaged by a valvedisc 32 fixedly attached to one end of a stem 30. The end wall 12 iscoaxially flanged between the valve housing 10 and an inlet nipple 22.The peripheral portion of the end wall 16 is similarly flanged betweenthe housing 10 and an outlet nipple 24.

The central portion of the end wall 16 is connected with the peripheralportion only by four narrow spokes 18. It is coaxially attached to oneaxial end of bellows 20 whose other end is attached to the stem 30. Theresilient bellows is tensioned at all times so as to keep the valve disc32 normally engaged with the valve seat 14. When the valve is opened,liquid flows through the valve in the direction of the arrow A from theinlet nipple 22 to the outlet nipple 24, and the pressure of the liquidassists in keeping the valve closed. The bellows 20 is not subject totransverse stresses under any operating conditions.

It can be opened by means of a hydraulic actuator 40 which includes aresilient pressure vessel 36 mainly consisting of two dished metalmembranes 38 whose circular rims are sealed to each other. One of themembranes rests on a fixed horizontal support 41. The other one isprovided with a central plunger 44 axially guided in a fixed bearing 42and attached to the armature 46 of a solenoid 48. The solenoid coil isarranged in series circuit with a current source 50 and a switch 52. Thevessel 36 is connected with the interior of the bellows 20 by theconduit 28 and with the body of liquid under pressure in the inletnipple 22 by a restricted bleeder tube 77.

When the switch 52 is closed, the solenoid 48 attracts its armature 46and thereby pushes the plunger 42 and the attached membrane 38 inwardlyof the vessel 36. Because of the great difference in flow sectionbetween the conduit 28 and the bleeder tube 77, the liquid displacedfrom the vessel 36 expands the bellows 20 and opens a passage in thevalve seat 14. When the switch 52 is opened, the vessel 36 expandsresiliently, and the valve 32 returns to the illustrated closedposition. Because of the pressure equalizing effect of the tube 77, onlylittle power is required of the solenoid 48.

The valve shown in FIG. 4 has a straight tubular housing 101 provided atits ends with inlet and outlet nipples 221, 241 respectively. Aperturedradial end walls 161, 162 of stainless steel are flanged between thehousing 101 and the nipples respectively, and the nipples and thehousing are protected by internal stainless steel liners 611, 621, 631.The spiderlike central portions of the end walls 221, 241 are providedwith blind bores 551, 552 in which the two ends of a stem 303 arereceived for limited axial movement.

The stem 303 passes through the wide central aperture of an annularpartition 122 approximately axially centered in the housing 101. Thestem 303 carries a fixed valve disc 323 on one side of the partition 122opposite a valve seat 142 on the latter, and a fixed disc 591 on theother side of the partition. A first bellows 202 is sealed to the endwall 161 and to the disc 591, and a second bellows 203 of the sameeffective cross section is fastened at one axial end to the end wall 162whereas the free rim of the second bellows is sealed to a collar 592 onthe valve disc 323. The effective cross section of the bellows 202 isequal to the area of the valve seat 142 which is covered by the valvedisc 323 in the closed valve. A helical compression spring 67 is coiledabout the valve stem 303 between the end wall 162 and the valve disc 323in the bellows 203. Conduits 281, 282 respectively permit fluid to beintroduced into the interiors of the bellows 202, 203 through the endwalls 161, 162.

In the embodiment illustrated, the conduit 282 connects the secondbellows 203 to the atmosphere, and the conduit 281 is connected to asource of pressure fluid through a control valve in a manner not furtherillustrated. The valve is shown in the position assumed when the bellows202 is filled with pressure fluid, hydraulic or pneumatic, under apressure sufi'icient to overcome the restraint of the spring 67 whichnormally holds the valve disc 323 against the valve seat 142. While thepressure of liquid or gas on the valve disc tends to keep the valveclosed, the same pressure is also applied to the bellows 203 and tendsto compress the bellows so that the valve-opening pressure in thebellows 202 need only be high enough to overcome the spring 67 and isindependent of the line pressure in the nipple 221, a feature valuablein high-pressure operations. In the open valve, the pressure applied bythe controlled fluid on the bellows 202 is compensated by the pressureon the be]- lows 203.

The valve shown in FIGS. 5 and 6 has a housing 102 whose innercylindrical wall is protected by a stainless steel liner 622. Inlet andoutlet nipples 222, 242 similarly protected by liners 612, 632 clampapertured end walls 123, 163 to the housing 102 as described withreference to other figures, but not explicitly shown in FIGS. 5 and 6.The large central aperture in the end wall 123 is normally closed by avalve disc 324 engaging a seat 143 on the wall 123 and fixedly fastenedto one end of a valve stem 304.

The stem 304 passes slidably through a spider 541 held in fixed positionby its sole spoke 531. The spider serves as one of two abutments for ahelical compression spring 571 coiled about the stem 304, the otherabutment being the bottom wall 601 of a narrow, cup-shaped receptacle581 which spacedly surrounds the spring. The stem 304 passes through thebottom wall 601,in fixed, sealing engagement. The end of the stem 304remote from the valve body 324 is covered with a sleeve 69 slidablyreceived in a guide bore 553 of the end wall 163 and having a closedhemispherical end which extends into a diametrical bore 68 in the endwall 163 which is rectangular in cross section. A wedge-shaped cam 71 isslidably received in the bore 68, and the materials of the sleeve 69 ofthe wedge 71 are selected to hold friction to a minimum. The cam 71 isrotatably attached to the inner end of a threaded spindle 73 whichextends outwardly from the bore 68 through a nut 74 fixedly fastened tothe end wall 163, and whose free outer end carries a handwheel 72.

A bellows 204 is mounted coaxially in the housing 102 between the endwall 163 and the rim 591 of the receptacle 581. The bore 68 communicateswith the interior of the bellows through an axial bore in the end wall163 and with the surrounding atmosphere through an opening 75 in a plug76 which otherwise closes the end of the bore 68 remote from the nut 74.

The valve shown in FIGS. 5 and 6 is normally held closed by the spring571 and by the pressure of the controlled fluid. It is opened by turningthe handwheel 72 in a direction to cause the rod 304 to be shiftedtoward the right, as viewed in FIG. 5, by the cam 71. The bellows 204 inthis instance does not operate the valve, but seals the valve openingmechanism from the fluid controlled by the valve.

If it is desired to operate the valve shown in FIGS. 5 and 6 by externalpressure fluid as well as manually, the conduit 70 is modified to leadoutwardly of the valve housing for connection to a source of pressurefluid, as described above with reference to the conduit 28, and astuffing box or similar seal is provided in the guide 553 to preventleakage from the chamber in the bellows 204 to the bore 68 in whichatmospheric pressure prevails.

Obviously, the aforementioned materials of construction for the valvesof the invention may be replaced by other materials if the operatingconditions permit. Bronze housings and other valve parts will thus besatisfactory under many conditions, and plastic parts may be mostsatisfactory when the pressure and temperature of the controlled fluidsare consistent with the working range of the plastics employed.

It is an advantageous feature of the valves of the invention that valvesdiffering from each other in many operating characteristics can beassembled quickly and conveniently from a small number ofinterchangeable parts because of the flanging of the end walls betweenthe valve housing and the inlet and outlet nipples. The bellows may bepreassembled with the associated end walls if so desired and withcup-shaped receptacles for those types of valves requiring suchreceptacles. The rims of the bellows are preferably secured to'engagingother elements by adhesive bonding or by heat sealing if the bellowsconsists of suitable plastic or similar material.

Metallic bellows may be soldered, brazed or welded by induction heatingto other metallic components. Adhesive bonds may be strengthened byknurling the exposed side of the plastic bellows after bonding.

What is claimed is:

1. A valve comprising, in combination:

a. a housing having an axis and two axial end portions open for flow ofa fluid through said housing in the direction of said axis;

b. a valve seat member in said housing defining an aperture extendingthrough said member in said direction;

c. a valve member axially movable in said housing toward and away from aposition of engagement with said valve seat member in which the valvemember seals said aperture;

. spider means fixedly fastened in said housing;

. an axially expandable and contractable bellows member in said housingdefining a sealed chamber therein,

1. one axial end of said bellows member being fixedly fastened to saidspider means, a

2. said valve seat member being axially interposed between said valvemember and the other axial end of said bellows member;

. a valve stem member fastened to said other axial end of said bellowsmember and to said valve member for moving said valve member toward andaway from said position during expansion and contraction of the bellowsmember;

. a conduit communicating with said chamber for flow of fluid into andout of said chamber; and

. an annular guide member fixedly mounted in said housing between saidvalve seat member and said other axial end and receiving said valve stemmember for guiding said valve member in said direction.

2. A. valve as set forth in claim ll, further comprising spoke meansfixedly fastened to said housing and to said guide member.

3. A valve as set forth in claim 2, further comprising yieldablyresilient means interposed between said guide member and said otheraxial end for moving said guide member and said other axial end awayfrom each other in said direction.

4. A valve as set forth in claim .3, wherein said resilient meansinclude a rigid, cup-shaped receptacle having a rim portion fastened tosaid other axial end and a bottom portion fixedly sealed to said valvestem member, and a spring member partly received in said receptacle andabuttingly engaging said bottom portion.

5. A valve comprising, in combination:

a. a housing having an axis and two axial end portions open for flow ofa fluid through said housing in the direction of said axis;

b. a valve seat member in said housing defining an aperture extendingthrough said member in said direction;

c. a valve member axially movable in said housing toward and away from aposition of engagement with said valve seat member in which the valvemember seals said aperture;

d. a spider member fixedly fastened in said housing;

e. an axially expandable and contractable bellows member in said housingdefining a sealed chamber therein, one axial end of said bellows memberbeing fixedly fastened to said spider member;

f. a valve stem member fastened to the other axial end of said bellowsmember and to said valve member for moving said valve member toward andaway from said position during expansion and contraction of the bellowsmember,

1. said spider member being formed with an axial bore movably receivinga portion of said valve stem member,

2. said portion of the valve stem member being sealed in said chamber;and

g. a conduit communicating with said chamber for flow of fluid into andout of said chamber.

6. A valve comprising, in combination:

a. a housing having an axis and two axial end portions open for flow ofa fluid through said housing in the direction of said axis;

b. a valve seat member in said housing defining an aperture extendingthrough said member in said direction;

. a valve member axially movable in said housing toward and away from aposition of engagement with said valve seat member in which the valvemember seals said aperture;

d. spider means fixedly fastened in said housing;

. an axially expandable and contractable bellows member in said housingdefining a sealed chamber therein, one axial end of said bellows memberbeing fixedly fastened to said spider means;

. a valve stem member fastened to the other axial end of said bellowsmember and to said valve member for moving said valve member toward andaway from said position during expansion and contraction of the bellowsmember;

a conduit communicating with said chamber for flow of fluid into and outof said chamber; and h. guide means guiding said valve member in saiddirection,

1. said guide means including two guide members axially spaced in saidhousing and formed with respective axially aligned openings therein,

2. said valve stem member being slidably received in said openings ofsaid guide members.

. A valve comprising, in combination:

a housing having an axis and including 1. a tubular housing member,

2. a tubular inlet member and a tubular outlet member axially alignedwith said housing member and axially offset from the same in oppositedirections, said inlet and outlet members being formed with respectiveopenings for axial flow of a fluid through said housing member;

b. a valve seat member flanged in said housing between said housingmember and one of said inlet and outlet members defining an apertureextending through said member in said direction;

c. a valve member axially movable in said housing toward and away from aposition of engagement with said valve seat member in which the valvemember seals said aperture;

d. a spider member fixedly flanged in said housing between the other oneof said inlet and outlet members, said spider member and said valve seatmember having respective guide portions formed with respective guideopenings;

e. an axially expandable and contractable bellows member in said housingdefining a sealed chamber therein, one axial end of said bellows memberbeing fixedly fastened to said spider means;

f. a valve stem member received in said guide openings and fastened tothe other axial end of said bellows member and to said valve member formoving said valve member toward and away from said position duringexpansion and contraction of the bellows member; and

g. a conduit communicating with said chamber for flow of fluid into anout ofsaid chamber.

@. A valve comprising, in combination:

a. a housing having an axis and two axial end portions open for flow ofa fluid through said housing in the direction of said axis;

b. a valve seat member in said housing having an axially directed seatportion about an aperture extending through said member in saiddirection;

a valve member axially movable in said housing toward and away from aposition of engagement with said valve seat member in which the valvemember seals said aperture;

spider means fixedly fastened in said housing;

. an axially expandable and contractable bellows member in said housingdefining a sealed chamber therein, one axial end of said bellows memberbeing fixedly fastened to said spider means; motion transmitting meansconnecting the other axial end of said bellows member to said valvemember for moving said valve member toward and away from said positionduring expansion and contraction of the bellows member;

. a conduit communicating with said chamber for flow of fluid into andout of said chamber;

. guide means guiding said valve member in said direction;

and

. fastening means for fastening said valve seat member in said housingin two alternative positions in which said seat portion faces towardsaid bellows member and away from said bellows member respectively.

9. A valve as set forth in claim 8, wherein said motion transmittingmeans include a valve stem member fastened to said valve member and tosaid other axial end, said guide means including an axial bore in saidspider member movably receiving a portion of said valve stem membersealed in said bellows member.

10. A valve as set forth in claim 8, wherein said valve member has twosealing faces tapering in opposite axial b-la directions for engagementwith said seat portion in said two positions of the valve seat memberrespectively.

1 l. A valve comprising, in combination:

a. a housing having an axis and two axial ends open for flow of a fluidthrough said housing in the direction of said axis;

. a valve seat member in said housing defining an aperture extendingthrough said member in said direction;

a valve member axially movable in said housing toward and away from aposition of engagement with said valve seat member in which the valvemember seals said aperture;

. spider means fixedly fastened in said housing;

. an axially expandable and contractable bellows member in said housingdefining a sealed chamber therein, one axial end of said bellows memberbeing fixedly fastened to said spider means;

. a valve stem member fastened to the other axial end of said bellowsmember and to said valve member for moving said valve member toward andaway from said position during expansion and contraction of the bellowsmember;

a conduit communicating with said chamber for flow of fluid into and outof said chamber; and

h. guide means guiding said valve member in said direction,

1. said guide means having two portions offset from said bellows memberin opposite directions and movably engaging respective axial portions ofsaid valve stem member.

12. A valve as set forth in claim 11, further comprising pressure meansfor forcing a fluid into said chamber through said conduit at a pressuresufficient for axially expanding said bel lows member and for therebyaxially moving said valve member.

' UNITED STATES PATENT oEETcE CERTIFICATE @F CGRRECTEQN Patent No. 73,637, 187 I Dated lagmarx 25. 1912 Inventofl s) Manfred Burger It iscertified that error appears in the above-identified patent and thatsaid Letters Patent are hereby corrected as shown below:

In the title page, after line 597 add:

November 20, 1968, Germany P 18 10 095.3

Signed and sealed this 15th day of August 1972.

(SEAL) Attest;

ROBER GOTTSCHALK EDWARD M. FLETCHER, JR.

Commissioner of Patents Attesting Officer

1. A valve comprising, in combination: a. a housing having an axis andtwo axial end portions open for flow of a fluid through said housing inthe direction of said axis; b. a valve seat member in said housingdefining an aperture extending through said member in said direction; c.a valve member axially movable in said housing toward and away from aposition of engagement with said valve seat member in which the valvemember seals said aperture; d. spider means fixedly fastened in saidhousing; e. an axially expandable and contractable bellows member insaid housing defining a sealed chamber therein,
 1. one axial end of saidbellows member being fixedly fastened to said spider means,
 2. saidvalve seat member being axially interposed between said valve member andthe other axial end of said bellows member; f. a valve stem memberfastened to said other axial end of said bellows member and to saidvalve member for moving said valve member toward and away from saidposition during expansion and contraction of the bellows member; g. aconduit communicating with said chamber for flow of fluid into and outof said chamber; and h. an annular guide member fixedly mounted in saidhousing between Said valve seat member and said other axial end andreceiving said valve stem member for guiding said valve member in saiddirection.
 2. said valve seat member being axially interposed betweensaid valve member and the other axial end of said bellows member; f. avalve stem member fastened to said other axial end of said bellowsmember and to said valve member for moving said valve member toward andaway from said position during expansion and contraction of the bellowsmember; g. a conduit communicating with said chamber for flow of fluidinto and out of said chamber; and h. an annular guide member fixedlymounted in said housing between Said valve seat member and said otheraxial end and receiving said valve stem member for guiding said valvemember in said direction.
 2. A valve as set forth in claim 1, furthercomprising spoke means fixedly fastened to said housing and to saidguide member.
 2. said portion of the valve stem member being sealed insaid chamber; and g. a conduit communicating with said chamber for flowof fluid into and out of said chamber.
 2. said valve stem member beingslidably received in said openings of said guide members.
 2. a tubularinlet member and a tubular outlet member axially aligned with saidhousing member and axially offset from the same in opposite directions,said inlet and outlet members being formed with respective openings foraxial flow of a fluid through said housing member; b. a valve seatmember flanged in said housing between said housing member and one ofsaid inlet and outlet members defining an aperture extending throughsaid member in said direction; c. a valve member axially movable in saidhousing toward and away from a position of engagement with said valveseat member in which the valve member seals said aperture; d. a spidermember fixedly flanged in said housing between the other one of saidinlet and outlet members, said spider member and said valve seat memberhaving respective guide portions formed with respective guide openings;e. an axially expandable and contractable bellows member in said housingdefining a sealed chamber therein, one axial end of said bellows memberbeing fixedly fastened to said spider means; f. a valve stem memberreceived in said guide openings and fastened to the other axial end ofsaid bellows member and to said valve member for moving said valvemember toward and away from said position during expansion andcontraction of the bellows member; and g. a conduit communicating withsaid chamber for flow of fluid into an out of said chamber.
 3. A valveas set forth in claim 2, further comprising yieldably resilient meansinterposed between said guide member and said other axial end for movingsaid guide member and said other axial end away from each other in saiddirection.
 4. A valve as set forth in claim 3, wherein said resilientmeans include a rigid, cup-shaped receptacle having a rim portionfastened to said other axial end and a bottom portion fixedly sealed tosaid valve stem member, and a spring member partly received in saidreceptacle and abuttingly engaging said bottom portion.
 5. A valvecomprising, in combination: a. a housing having an axis and two axialend portions open for flow of a fluid through said housing in thedirection of said axis; b. a valve seat member in said housing definingan aperture extending through said member in said direction; c. a valvemember axially movable in said housing toward and away from a positionof engagement with said valve seat member in which the valve memberseals said aperture; d. a spider member fixedly fastened in saidhousing; e. an axially expandable and contractable bellows member insaid housing defining a sealed chamber therein, one axial end of saidbellows member being fixedly fastened to said spider member; f. a valvestem member fastened to the other axial end of said bellows member andto said valve member for moving said valve member toward and away fromsaid position during expansion and contraction of the bellows member, 6.A valve comprising, in combination: a. a housing having an axis and twoaxial end portions open for flow of a fluid through said housing in thedirection of said axis; b. a valve seat member in said housing definingan aperture extending through said member in said direction; c. a valvemember axially movable in said housing toward and away from a positionof engagement with said valve seat member in which the valve memberseals said aperture; d. spider means fixedly fastened in said housing;e. an axially expandable and contractable bellows member in said housingdefining a sealed chamber therein, one axial end of said bellows memberbeing fixedly fastened to said spider means; f. a valve stem memberfastened to the other axial end of said bellows member and to said valvemember for moving said valve member toward and away from said positionduring expansion and contraction of the bellows member; g. a conduitcommunicating with said chamber for flow of fluid into and out of saidchamber; and h. guide means guiding said valve member in said direction,7. A valve comprising, in combination: a. a housing having an axis andincluding
 8. A valve comprising, in combination: a. a housing having anaxis and two axial end portions open for flow of a fluid through saidhousing in the direction of said axis; b. a valve seat member in saidhousing having an axially directed seat portion about an apertureextending through said member in said direction; c. a valve memberaxially movable in said housing toward and away from a position ofengagement with said valve seat member in which the valve member sealssaid aperture; d. spider means fixedly fastened in said housing; e. anaxially expandable and contractable bellows member in said housingdefining a sealed chamber therein, one axial end of said bellows memberbeing fixedly fastened to said spider means; f. motion transmittingmeans connecting the other axial end of said bellows member to saidvalve member for moving said valve member toward and away from saidposition during expansion and contraction of the bellows member; g. aconduit communicating with said chamber for flow of fluid into and outof said chamber; h. guide means guiding said valve member in saiddirection; and i. fastening means for fastening said valve seat memberin said housing in two alternative positions in which said seat portionfaces toward said bellows member and away from said bellows memberrespectively.
 9. A valve as set forth in claim 8, wherein said motiontransmitting means include a valve stem member fastened to said valvemember and to said other axial end, said guide means including an axialbore in said spider member movably receiving a portion of said valvestem member sealed in said bellows member.
 10. A valve as set forth inclaim 8, wherein said valve member has two sealing faces tapering inopposite axial directions for engagement with said seat portion in saidtwo positions of the valve seat member respectively.
 11. A valvecomprising, in combination: a. a housing having an axis and two axialends open for flow of a fluid through said housing in the direction ofsaid axis; b. a valve seat member in said housing defining an apertureextending through said member in said direction; c. a valve memberaxially movable in said housing toward and away from a position ofengagement with said valve seat member in which the valve member sealssaid aperture; d. spider means fixedly fastened in said housing; e. anaxially expandable and contractable bellows member in said housingdefining a sealed chamber therein, one axial end of said bellows memberbeing fixedly fastened to said spider means; f. a valve stem memberfastened to the other axial end of said bellows member and to said valvemember for moving said valve member toward and away from said positionduring expansion and contraction of the bellows member; g. a conduitcommunicating with said chamber for flow of fluid into and out of saidchamber; and h. guide means guiding said valve member in said direction,12. A valve as set forth in claim 11, further comprising pressure meansfor forcing a fluid into said chamber through said conduit at a pressuresufficient for axially expanding said bellows member and for therebyaxially moving said valve member.